Because $this->_config['dbname'] is mandatory, if it misses, then you have an exception thrown by Zend_Db_Adapter_Abstract::_checkRequiredOptions() before entering in Zend_Db_Adapter_Oracle::_connect()

Posted by Steve Jordan (stevejordan) on 2009-03-05T08:44:18.000+0000

I see what your saying.
It sounds like a good idea to remove code which will never be run.

But the problem which I was having (with the empty Exception messages) will still occur in your replacement code, because you still have the @ suppressing error messages.